Ambient or Patagonia nano-air (or nano air light) would be my vote. Cool to cold weather active hunts, I never take the ambient off, I actually have the arrowhead MDWi version by Sitka…but essentially the same thing. Loved it so much I bought two more as back ups for a long time coming if they discontinue. Merino base, ambient (mdwi), dehaviland, dew point, Grumman has me covered for just about anything. Merino and ambient never come off because the ambient breathes so well, just layer over the top of that as needed.
I love my Patagonia nano-air and N-A lights equally as much though. I like those a bit better than the Atom, find that they breathe better.
The cirque is really warm comparatively and I replace the ambient with that if it’s REALLY cold. Definitely doesn’t breathe nearly as well…even the cirque light is much warmer than an ambient or nano air IMO and unless it’s at freezing temps or a little less, have to strip those if I’m hiking hard. Not so with the ambient, but the cirque is a lot more wind resistant too, which is a plus.
